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Myeloproliferative neoplasms (MPNs) are a group of blood cancers closely related to leukemia, lymphoma, and myeloma. Each type of MPN involves the overproduction of one or more types of blood stem cells — red blood cells, white blood cells, or platelets — in the bone marrow. The excess of abnormal blood cells can lead to various symptoms including fatigue, headaches, blurred vision, and night sweats. The three main types of MPNs are polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (MF or PMF).
In the majority of cases, there is no cure for MPNs. MPNs grow slowly, and most people can live a near-normal lifespan with treatment. Treatment options for MPNs include chemotherapy, targeted medications like kinase inhibitors, and supportive care to help manage symptoms caused by the high number of blood cells.
MPNs are classified as rare diseases because each type affects fewer than 200,000 people in the United States. Based on 2010 U.S. health care data, it’s estimated that:
The American Cancer Society estimates that approximately 9,280 new cases of CML will be diagnosed in the United States in 2024, with 5,330 cases in men and 3,950 in women.
According to the National Cancer Institute, there were 69,533 Americans living with CML in 2021.
Like other cancers, MPNs are caused by genetic mutations (changes, or variants) that allow some cells to divide and grow uncontrollably. There are two main types of mutations, inherited and acquired. Most cancer is caused by acquired mutations, which occur throughout a person’s life due to aging and exposure to carcinogens (something that can cause cancer) such as radiation, smoking, and certain chemicals and viruses.
Genetic mutations that encourage uncontrolled cell growth cause cells to divide too quickly and without normal regulation, leading to more and more changes. When these disordered cells begin to invade nearby tissues or break off and migrate to other locations, they become cancerous.
Specific genetic mutations most often associated with the three most common MPNs include the JAK2, CALR, MPL, and CSF3R gene markers. CML is often associated with the Philadelphia chromosome (Ph-positive). This genetic change, known as BCR-ABL, was named after the city where it was discovered.
Age is an important risk factor for developing MPNs. Most people are diagnosed during or after their 60s. Other risk factors for developing MPNs can include exposure to radiation and carcinogenic chemicals including benzene. In rare cases, more than one person in a family may develop MPNs. However, MPNs are not considered to be inherited diseases.
Read more about the risk factors and causes of MPNs.
Many people don’t experience any symptoms of MPNs when they’re diagnosed. Some of the most common symptoms across types of MPNs include fatigue, itching, night sweats, headaches, dizziness, and blurred vision. Some symptoms, such as abnormal bleeding, blood clots, enlarged spleen, and bone and joint pain, are more common in some types of MPNs than others.
Some symptoms, including hair loss, nausea, diarrhea, vomiting, mouth sores, and neuropathy (tingling or numbness in the extremities), are more likely to be side effects of treatment for MPNs. Your doctor can help you understand where symptoms are coming from and how best to manage them.
Read more about MPN symptoms.
In all MPNs, blood cells grow abnormally, leading to an overproduction of blood cells that don’t function properly. MPNs are categorized based on which type of blood cell is overproduced — red blood cells, white blood cells called neutrophils, platelets, or multiple types of cells. The different types of MPNs are identified based on the specific genetic mutations found in the cancer cells. MPNs and other blood cancers such as leukemia and lymphoma are all closely related, and one type may change into another type over time.
Other types of MPNs include:
Read more about different types of MPNs.
It can take many years for MPNs to start causing symptoms, and many people have symptoms for a long time before going to their doctor for a diagnosis. For these reasons, MPNs are often discovered when blood tests ordered for another health issue return abnormal results.
Once an MPN is suspected, doctors will usually take a medical history to assess symptoms and any risk factors that might make an MPN more likely. A physical examination can check for signs such as an enlarged spleen.
Blood samples are taken to perform tests including:
Bone marrow biopsy and bone marrow aspiration are similar procedures that obtain samples of liquid and solid bone marrow using a needle. Bone marrow is used for visualizing abnormal cells and performing special tests that include immunohistochemistry and genetic testing. Genetic testing to determine which mutations are present in cancer cells may be performed on blood or bone marrow. These test results are often necessary to confirm the diagnosis of an MPN.
Before diagnosing an MPN, the doctor will also rule out other MPNs or unrelated conditions that could potentially cause similar symptoms and test results.
Read more about how MPNs are diagnosed.
In cases of MPNs where people are not experiencing any symptoms and their risk for developing dangerous complications is considered low, doctors may recommend a watch-and-wait approach rather than beginning treatment immediately. If your risk increases or symptoms develop, your doctor may recommend starting treatment.
Hematologist-oncologists — doctors who specialize in blood diseases and cancer — recommend treatments depending on what type of MPN you have, what treatments you have already tried, and your condition and risk factors. Treatments for MPNs may include chemotherapy and targeted medications such as Janus kinase (JAK) inhibitors, tyrosine kinase inhibitors (TKIs), and interferons. In rare cases, some people with MPNs may be candidates for stem cell transplants (also known as bone marrow transplants), which can potentially cure MPN.
Supportive treatments that can help manage MPN symptoms include medication to reduce the number of excess blood cells; medication, splenectomy, or radiation to reduce an enlarged spleen; and phlebotomy or apheresis to remove excess blood cells. Other medications, such as aspirin or blood thinners, may be given to reduce the risk of dangerous complications such as blood clots.
Especially rare types of MPNs such as CNL, CEL, and MPN unclassifiable do not have standard treatment regimens.
Read more about treatment options for MPNs.
People with MPNs are likely to have comorbidities — other health conditions in addition to MPN. When additional health problems make MPNs harder to treat, they are considered complications. Comorbidities are believed to contribute significantly to the disease burden in MPNs, especially fatigue. Having additional health conditions also raises the risk of death in people with MPNs.
People diagnosed with MPNs have a higher risk than the general population for developing:
There are steps you can take to reduce your risk for cardiovascular problems. Most comorbidities can be managed with lifestyle changes or medications. Treating comorbidities may improve your quality of life and help reduce the risk of death.
Read more about comorbidities of MPN and related conditions.
In most cases, MPNs aren’t curable. People with MPNs may have a shorter life expectancy than others their age who do not have an MPN. However, with treatment, most people with MPNs can live for many years and may live a near-normal life span. People with myelofibrosis are more likely to have a shortened life span than people with ET or PV. Complications of MPNs such as infection, stroke, and heart attack contribute to early death in people with MPNs.
Your doctor can help you understand the risk factors that contribute to your prognosis. These may include the type of MPN you have, your age and overall condition, any additional health problems, and how you treat your MPN.
In the 1840s in France, Germany, and Scotland, there were early descriptions of people with high white blood cell counts and enlarged spleen — most likely these were describing CML. During this period, arsenic was typically prescribed as a treatment for CML. Phlebotomy (drawing blood) has been a mainstay of treatment for PV for more than 100 years, although it’s now often combined with medications.
MPNs were first categorized in 1951 by Dr. William Dameshek, founder of the academic and research journal Blood, architect of the American American Society of Hematology, and founder of the International Society of Hematology.
In 1960, scientists discovered the association between the Philadelphia chromosome and CML. In 2005, scientists found more genetic mutations associated with MPNs, beginning with a JAK2 mutation, followed by myeloproliferative leukemia virus oncogene (MPL) and calreticulin (CALR) mutations.
In the early 20th century, CML was primarily treated with radiation therapy and later with traditional chemotherapy or interferons. In the 1980s, allogeneic stem cell transplants (using cells from donors) became a focus of treatment in people who were eligible. Since medications of the tyrosine kinase inhibitor (TKI) class became available in 1998, these drugs have become first-line therapy for CML and some other MPNs.
Before the World Health Organization (WHO) reclassified this group of blood cancers in 2008, they were known as myeloproliferative disorders. The categorization of MPN types was more recently revised by the WHO in 2016. Criteria for diagnosing types of MPNs now include which specific genetic mutations are involved. Starting in 2009, doctors developed scoring systems to help predict the outlook for people with MPNs by considering different risk factors.
Researchers are working to find new ways to predict and treat MPNs by studying genetic markers and developing more effective treatments. Current options like chemotherapy, targeted therapies, and supportive care help manage symptoms and improve quality of life. With early diagnosis and proper care, many people can live well with MPNs.
On myMPNteam, the social network for people with myeloproliferative neoplasms and their loved ones, more than 4,000 members come together to ask questions, give advice, and share their stories with others who understand life with MPNs.
Have you or a loved one been diagnosed with MPNs? Are you looking for support and information on managing life with the condition? Share your experience in the comments below, or start a conversation by posting on your Activities page.
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How Does Not Having A Spleen Affect Mpns And Liver?
Fatima Sharif, MBBS, FCPS
graduated from Aga Khan University, Pakistan, in 2017 after completing medical school.
Learn more about her here.
Kelly Crumrin
is a senior editor at MyHealthTeam and leads the creation of content that educates and empowers people with chronic illnesses.
Learn more about her here.
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Great information. I become more secure when I read articles like this. I am a 10year MF patient When 1st DX they told me 3-6 years. Of course this scared the heck out of me. I think one of… read more
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